1. Field of the Invention
The present invention relates to a method for designing a circuit, particularly having an active component, in, for example, a high-frequency circuit.
2. Description of the Background Art
According to the conventional art, for the design of electronic circuits, means are known for dimensioning electronic components and establishing suitable operating points for electronic components. Methods, which depict circuit parameters at the reflection factor level, mainly in the passive part of the reflection factor level, called a Smith chart hereafter, namely, particularly in form of isohypses, play a special role here. Thus, for example, in the input and output Smith chart of an active component at a given operating point, lines are drawn as loci of a constant power gain depending on the input or output reflection factor. The Smith chart per se as a reflection factor diagram is hereby first a small-signal method.
Essential parameters for a power amplifier are the linear output power, quantified hereinafter by the compression point, P-1dB, the power added efficiency, designated as “PAE” in the following text, and the amount of the power gain, measured on a logarithmic scale, characterized by G (gain).
Smith charts with drawn isohypses, for example, of a constant Rollet's k factor, permit a designer to reach conclusions on the functionality at a considered operating point of the component. The isohypses are typically generated in an automated manner.
Design technology, moreover, allows the automatic generation of isohypsic regions for quantities, which can be derived in the output characteristic field from the local circuit properties. With the aid of the postprocessor for “Advanced Design System” (ADS) from Agilent, for example, isohypses of this type can be automatically generated with commands such as contour(max_gain(S)).
These numerical calculations require considerable effort to determine precisely the required properties of the amplifier or an active component.